As in the need for hip and knee replacements, patients requiring an ankle replacement no longer have a fully functional ankle. The most common end-stage ankle complications arise from arthritic pain either from old age or previous trauma. For many years, arthrodesis, or ankle fusion, was the primary technique for reducing the pain in patients; however, fusing the ankle bones together greatly reduces the joint's range of motion, and could potentially cause serious alterations in gait, which often leads to additional joint and mobility complications. To many people, having a fully functional ankle is vital in maintaining an active and healthy lifestyle.
In an effort to produce an alternative to arthrodesis, developers began designing and constructing ankle replacement prosthesis in the early 1970s. Throughout the following decades, researchers have yet to design a proven reliable, long lasting replacement. The United States Food and Drug Administration (FDA) approved designs being used in the United States today are the Agility, INBONE, Salto-Talaris, and Eclipse total ankle replacements, which are all two-component designs. A fifth, three-component design called the Scandinavian Total Ankle Replacement was recently approved by the FDA in May 2009. Many more types are available in other countries; mostly in Europe. The ankle replacements available typically contain very similar components: a tibial component, a talar component, and a polyethylene insert that serves as a bearing between the other two components. The most significant differences are how the components are fixed to the tibia and talus, the contour of the bearing-talar component surface, and the type of outer coating applied to the metallic components.
A major issue with current designs on the market is longevity of the prosthesis. Most complications are associated with wound healing, polyethylene bearing wear and fracture, and dislocation of components. Overcoming the high stresses on such small components is the primary challenge for designers. High concentration of stresses at the point of fixation, caused by the transfer of energy through ankle movement, can ultimately cause component loosening and overall prosthesis failure.
Improved ankle replacement prosthesis and methods which address one or more of the above-described problems, or which address other problems or provide other advantages not discussed above, would be a significant improvement in the field of ankle replacement.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.